Suppose that 5.00 mL of blood serum containing an unknown concentration of potassium, [K+]i, gave an atomic emission signal of 3.00 mV. After the addition of 1.00 mL of 30.0 mM K + and dilution of the mixture to 10.00 mL, the emission signal increased to 4.00 mY. (a) Find the concentration of added standard, [S]r. in the mixture. (b) The initial 5.00-mL sample was diluted to 10.00 mL. Therefore the serum potassium concentration decreased from [K+]i to [K + ]r = HK + ]i· Use Equation 5-6 to find the original K+ content of the serum, [K+]i.